Typically, a variable intake module is placed between an intake manifold and cylinder head of an internal combustion engine. The variable intake module forms a strong tumble within a combustion chamber by adjusting the flow of intake air, thereby resulting in a lean-burn of fuel. A flap is installed inside the variable intake module at a path where the exterior air is taken in. The flap pivots to vary the area and shape of the above path, thereby inducing a strong tumble or swirling of the air/fuel mixture inside the combustion chamber.
Injectors are equipped in the cylinder head for injecting fuel. The injectors are installed at a fuel rail provided with fuel under high pressure. The fuel rail is installed in the cylinder head to maintain the installation disposition of the injector. An injector, fuel rail, and variable intake module are equipped around the intake port of the cylinder head. The injector is equipped to provide fuel and the variable intake module is equipped to form a tumble of the fuel. Typically, the fuel rail installed with the injector is assembled first, and subsequently, the variable intake module is assembled.
However, if pluralities of the above components are located on the intake port side of the cylinder head, the components frequently interfere with each other. Therefore, a portion of the variable intake module should be either reduced in size or removed to prevent interference from occurring. However, the variation of the variable intake module reduces the coupling area between the variable intake module and intake manifold, thereby causing insufficient sealing around the coupling portion therebetween. Furthermore, a narrow space between the injector, fuel rail, and variable intake module deteriorates the assembly.